An outbreak of pertussis is continuing in Douglas County, with 86 cases being confirmed through October, and another 46 possible cases that are still under investigation, according to the Lawrence-Douglas County Health Department.

That compares to just 17 cases that were confirmed in all of 2011, the department said.

Pertussis, also known as whooping cough, is a highly contagious disease caused by bacteria. It is easily preventable with immunizations, but health officials say those immunizations do wear off, and they recommend that even adults check with their doctors to see if they need booster shots.

The sickness can strike people of any age, but it is most common in infants younger than 6 months of age and children 10-14 years of age.

The disease causes symptoms similar to the cold or flu. Early symptoms include runny nose, sneezing, fever and cough, which generally last one to two weeks. The next stage includes uncontrolled coughing spells followed by a whooping noise when the person breathes in.

That second stage can last four to six weeks and can cause serious complications, or even death, especially among infants.

Health officials recommend the following steps to prevent pertussis:

• Giving a series of immunization shots to children at 2, 4, 6 and 15 months of age, and again before a child enters school.

• Giving booster doses to adolescents 11 to 18 years of age and into adulthood.

• Recommending the “Tdap” immunization (tetanus, diphtheria and pertussis) to women of newborns and any primary caregivers of the newborn who have not previously been vaccinated before the newborn is discharged from the hospital or birthing center.

• People with pertussis should avoid contact with others until they have taken five full days of an appropriate antibiotic, or they should remain in respiratory isolation for three weeks if they do not take an appropriate antibiotic.

• Prompt use of antibiotics in a household is helpful in limiting other cases.

• And in a day care setting, antibiotics should be given to household contacts and other close contacts of cases. Children who develop symptoms within 21 days of exposure are excluded from day care until a diagnosis can be made.